LANDOVER, Md. - With zero help from his offensive line, Robert Griffin III repeatedly wound up on the turf until leaving with a concussion after being sacked three times and fumbling twice Thursday night in the Washington Redskins' 21-17 exhibition victory over the Detroit Lions.

Griffin went 2 for 5 for 8 yards on four possessions for Washington (2-0). On his final play, early in the second quarter, he started to scramble but dropped the ball despite no contact. As the quarterback went to the ground to try to corral the loose ball, Lions defensive end Corey Wootton landed on Griffin.

Redskins coach Jay Gruden said Griffin had a concussion but that the QB's right shoulder, which also was hurt, would be OK. Gruden said he had "no idea" how long Griffin will be sidelined with the head injury.

The coach added he "would imagine, depending how long" Griffin is out, "he's still going to be our starter."

For Detroit (1-1), Matthew Stafford looked good, going 6 of 8 for 78 yards and leading one scoring drive that ended with Matt Prater's 49-yard field goal.

When Griffin got hurt, he stayed down on the field for about 5 minutes and was tended to by trainers, while some teammates kneeled nearby. When Griffin eventually rose, he slowly stepped to the sideline, then kept going until he left the field and entered the tunnel that leads to the Redskins' locker room. Griffin gave a thumb's up to spectators as he trudged away.

The 2012 NFL Offensive Player of the Year's career has been marked by injuries and, the past two seasons, benchings. Despite public critiques from Gruden last year, Griffin was named the starting QB in February.

Gruden repeatedly said during training camp that he had seen progress from Griffin, but there was little evidence of that Thursday, thanks in part to little pass protection. Washington's offensive line was without Pro Bowl left tackle Trent Williams but did include the other four starters, including No. 5 overall draft pick Brandon Scherff at right guard.

Griffin's first fumble was recovered by the Redskins after a strip-sack on their opening possession. Early on, he had one pass batted down by linebacker Tahir Whitehead. Griffin later was driven to the turf by linebacker DeAndre Levy on a delayed blitz, and he was slammed down by defensive end Phillip Hunt, who blew past backup left tackle Willie Smith.

It capped a rough week for Griffin, who caused a national "firestorm," to use his word, with comments in a television interview about striving to be the best quarterback in the NFL. He complained that his remarks were taken out of context, saying after practice Tuesday: "It's unfortunate that my name keeps getting used for headlines for people to click on stories."